AutoCodes – Mercedes-Benz – P0177 Mercedes-Benz

P0177 Mercedes-Benz Code - Fuel Composition Sensor Circuit Range/Performance

Quick Answer

Fuel Composition Sensors are used to determine the amount of ethanol alcohol in the gasoline. Common causes include Flexible Fuel (FF) sensor to Vehicle Power (VPWR) circuit harness open or shorted, FF to VPWR circuit poor electrical connection, Open in FF sensor signal circuit. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0177 Mercedes-Benz indicates Fuel Composition Sensor Circuit Range/Performance.
Common causes: Common causes include Flexible Fuel (FF) sensor to Vehicle Power (VPWR) circuit harness open or shorted, FF to VPWR circuit poor electrical connection, Open in FF sensor signal circuit.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 4,758

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0177 Mercedes-Benz Description

Fuel Composition Sensors are used to determine the amount of ethanol alcohol in the gasoline. Normally, a gasoline engine should not have more than 10% ethanol alcohol in the fuel for proper operation. Some vehicles have a Flexible Fuel (FF) system on them that allow them to run on up to 85% ethanol alcohol in the fuel. The fuel composition sensor sends a frequency modulated signal to the engine controller which is proportional to the alcohol content of the fuel. The injector pulse width and the ignition timing are modified for the increased alcohol content. It takes almost twice the amount of alcohol compared to gasoline to produce the same power.

OBDII Code P0177 Mercedes-Benz - Fuel Composition Sensor Circuit Range/Performance - AutoCodes.com — P0177 Mercedes-Benz Code - Fuel Composition Sensor Circuit Range/Performance

What does this mean?

What are the Possible Causes of the DTC P0177 Mercedes-Benz?

Flexible Fuel (FF) sensor to Vehicle Power (VPWR) circuit harness open or shorted
FF to VPWR circuit poor electrical connection
Open in FF sensor signal circuit
Short to ground in FF sensor signal circuit
Fuel contamination

How to Fix the DTC P0177 Mercedes-Benz?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

Replaced Fuel Composition Sensor

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0177 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0177 Mercedes-Benz code?

Need more information on how to fix the P0177 Mercedes-Benz code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0177 Mercedes-Benz code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0177 Mercedes-Benz Code

1. What does the OBDII code P0177 mean on a Mercedes-Benz?

P0177 indicates a problem with the fuel composition sensor circuit, specifically a range or performance issue, which can affect the vehicle's ability to monitor fuel quality.

2. What are the common symptoms of code P0177 in a Mercedes-Benz?

Common symptoms include reduced fuel efficiency, rough idle, poor engine performance, and, in some cases, the Check Engine Light illuminating.

3. What causes the P0177 code to appear on a Mercedes-Benz?

Possible causes include a faulty fuel composition sensor, damaged wiring or connectors in the sensor circuit, contaminated fuel, or even a malfunctioning engine control module (ECM).

4. Can contaminated fuel trigger code P0177 in a Mercedes-Benz?

Yes, contaminated or poor-quality fuel can interfere with the fuel composition sensor's readings and trigger the P0177 code.

5. How do you diagnose the P0177 code on a Mercedes-Benz?

Diagnosis involves scanning the vehicle for additional codes, inspecting the fuel composition sensor and its wiring, and testing the sensor's output to confirm proper operation.

6. Can I drive my Mercedes-Benz with the P0177 code?

While the car may remain operational, driving with this code can lead to poor performance and increased fuel consumption. Itâ€™s best to address the issue promptly.

7. How is the P0177 code fixed on a Mercedes-Benz?

Repairs may include replacing the fuel composition sensor, repairing or replacing damaged wiring, cleaning the fuel system, or updating the ECM software.

8. How much does it cost to fix the P0177 code on a Mercedes-Benz?

Repair costs vary but typically range from $100 to $500, depending on whether the sensor, wiring, or ECM requires attention.

9. Can a software update resolve the P0177 code in a Mercedes-Benz?

In some cases, a software update for the ECM may resolve the issue if the problem stems from incorrect sensor readings due to outdated programming.

10. How can I prevent the P0177 code from recurring in my Mercedes-Benz?

To prevent recurrence, use high-quality fuel, perform regular maintenance on the fuel system, and inspect wiring and connectors during routine checkups.